Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for credit loss	$ 7,285	$ 5,579
Property and equipment, accumulated depreciation	$ 533,450	$ 516,988
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	169,392	169,294
Common stock, shares outstanding	169,392	169,294